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end of 1993. Although HCFCs are ozone-depleting substances, they are far less destructive than the CFCs. Amofoam (800-241-4403) offers two product lines that contain recycled materials: AmofoamRCY and Amofoam-RCX. Both products have 50% total recycled content: 25% post-industrial recycled polystyrene and 25% post-consumer recycled polystyrene. The RCY product has been on the market for several years. The RCX product, which is aimed at residential markets, is thinner (1/2 in. or % in.) and is faced with polyethylene on both sides. It was introduced in 1995. Amofoam products are available only east of the Rockies, except by special order. Expanded polystyrene (EPS, or bead board) is produced by expanding beads of polystyrene in a mold, then slicing the block of molded foam into boards. Pentane, which does not deplete ozone, is the blowing agent. Because EPS is the only rigid-foam insulation not produced with ozone-depleting substances, it has gained the favor of environmentally concerned builders and designers. Some manufacturing plants, particularly those in California, have pentane-collection systems to reduce plant emissions. In addition, several suppliers of polystyrene beads have introduced low-pentane beads that use about half of the pentane found in typical beads. While most EPS board stock is 0.9 pef to I pef, densities up to 2 pef are available from most manufacturers. At higher densities, compressive strength is greater, R-value is higher, and moisture resistance is better-as is needed below grade. EPS in density of 1.5 pef to 2.0 pef is commonly used in insulated foundation forms for below-grade applications. Cost is greater for the higher-density EPS. AFM Corporation (800-255-0176) began incorporating a borate insect repellent into some of its EPS foam in 1990. The repellent is now standard in AFM's R-Control panels and available as an option in other EPS products, such as its Diamond Snap-Forms (bottom photo, p. 52). The repellent is added to address the concern that termites and carpenter ants often tunnel through foam-core panels or foam insulation on the outside of foundations and may use the foam as a way into a house. So far, the borate treatment seems to work successfully. A final development with EPS is the appear- ance of polyethylene facings on some products to improve durability, both for roofing products and for foam sheathing (top photo, p. 52). With a more durable product, we are likely to begin seeing more EPS sold in building-supply yards, where it's rarely been stocked in the past. Polyisocyanurate-foam insulation is widely used as an exterior insulative wall sheathing and as roof insulation. Most products are foil-faced, 50 Fine Homebuilding paint and within minutes expands 100% to fill all voids in a building cavity. Excess is trimmed away with a handsaw. although other, more-rugged facings have appeared in recent years, such as polymer-coated glass fiber. Polyiso foam used to be blown with CFC-II. The blowing agent that is being used now, HCFC-14I b, is much less damaging to ozone. However, this one is among the worst of the HCFCs, relative to ozone depletion, and is slated to be phased out by 2003. Suppliers of chemical blowing agents are hard at work on so-called third-generation compounds that have no impact on ozone. Water is replacing hydrocarbons in polyurethane ins olation to polyisocyanurate-foam board stock, spray polyurethane is used in cavities or applied over surfaces to be insulated. The use of spraypolyurethane insulation dropped off significantly as the cost of the CFC-II blowing agent increased. But now that the shift to HCFC-141 b is complete (as of January I, 1994) and as the cost of wet-spray cellulose insulation increases, use of polyurethane is picking up again. The most significant developments in this area - are products foamed with carbon dioxide or water in place of CFCs or HCFCs. The leading prod- Chemically similar Spray it on, _w it flat. Icynene, an open-ceU polyisocyanurate insulation, is sprayed on like uct in this area is lcynene (800-758-7325), a carbon-dioxide-blown, open-cell modified polyurethane foam developed in Canada about 10 years ago (photo above). The company recently expanded into the United States and now has 60 licensed installers in 25 states. lcynene is sprayed into open wall cavities in a very thin layer, almost like spray paint, and it expands immediately. In a few seconds lcynene expands IOO-fold, filling the cavity. Because the expansion is so rapid and so great, installers often overfill cavities and have to go back and cut off the excess using a handsaw. As an open-cell foam, lcynene is spongy to the touch. It adheres extremely well to most surfaces and is effective at providing an air seal. Marketed in Canada as InSealation, lcynene expands to a density of approximately 0.5 pef, or roughly one-fourth the density of standard spray polyurethane or polyiso board stock. Its insulating value is approximately R-3.6 per inch. lcynene recently introduced a second prod- uct designed for installation into closed cavities. A carefully measured volume of the unexpanded foam is poured into the cavity, where it expands from bottom to top to fill the cavity. This product insulates to R-4 per inch. Also, lcynene Photo this page: Steve Culpepper